public class TestBase{
    public static void main(String[] args){
        Base base = new Derived();
        Base base1 = new Fork();
        Derived d = (Derived)base;
        Fork f = (Fork)base1;
        System.out.println("base.n"+base.n);
        //System.out.println("base.v"+base.v);
        base.show();
        System.out.println("d.n"+d.n);
        System.out.println("d.v"+d.v);
        d.show();
        d.disp();
        f.out();
    }
}